Studies on the synthesis, characterization and reactivity of new ferrocenylacetylenylbiphenyl derivatives

Article abstract of DOI:10.1016/j.poly.2007.02.023

A series of ferrocenylacetylenylbiphenyl derivatives Fc-C{triple bond, long}C{single bond}R [R = C₆H₄{single bond}C₆H₅ (1), C₆H₄{single bond}C₆H₄{single bond}I (2), C₆H₄{single bond}C₆H₄{single bond}NO₂ (3), C₆H₃(NO₂){single bond}C₆H₄I (4)] and Fc-C{triple bond, long}C{single bond}R′{single bond}C{triple bond, long}C{single bond}R″ [R″ = Fc, R′ = C₆H₄{single bond}C₆H₄ (5), C₆H₃(NO₂){single bond}C₆H₄ (6); R″ = C₆H₅, R′ = C₆H₄{single bond}C₆H₄ (7)] were synthesized from FcC{triple bond, long}CH and biphenyl iodides by the Castro-Stephens and Sonogashira coupling reactions, in which compounds 1, 2, 3, 4, 6 and 7 are new. Seven new complexes [Fc-C{triple bond, long}C{single bond}R][Co₂(CO)₆] [R = C₆H₄{single bond}C₆H₅ (8), C₆H₄{single bond}C₆H₄{single bond}I (9), C₆H₄{single bond}C₆H₄{single bond}NO₂ (10), C₆H₃(NO₂){single bond}C₆H₄I (11)] and [Fc-C{triple bond, long}C{single bond}R′{single bond}C{triple bond, long}C{single bond}R″] [Co₂(CO)₆]₂ [R″ = Fc, R′ = C₆H₄{single bond}C₆H₄ (12), C₆H₃(NO₂){single bond}C₆H₄ (13); R″ = C₆H₅, R′ = C₆H₄{single bond}C₆H₄ (14)] were obtained by the reaction of the ligands Fc-C{triple bond, long}C{single bond}R and Fc-C{triple bond, long}C{single bond}R′{single bond}C{triple bond, long}C{single bond}R″ with Co₂(CO)₈, respectively. Compounds 1-7 and their complexes 8-14 have been characterized by element analysis and spectroscopy, as well as by X-ray diffraction for 1, 4, 8, 9 and 11. The electrochemical data of compounds 1-12 have been obtained by cyclic voltammetry.

Full text of DOI:10.1016/j.poly.2007.02.023

Polyhedron 26 (2007) 3153–3160
www.elsevier.com/locate/poly
Studies on the synthesis, characterization and reactivity of new
ferrocenylacetylenylbiphenyl derivatives
a,
a
a
a
b
Quan-Ling Suo *, Yue-Guang Bai , Yi-Bing Wang , Li-Min Han , Lin-Hong Weng
a
Chemical Engineering College, Inner Mongolia University of Technology, Hohhot 010051, PR China
b
Department of Chemistry, Fudan University, Shanghai 200433, PR China
Received 14 December 2006; accepted 15 February 2007
Available online 1 March 2007
Abstract
A series of ferrocenylacetylenylbiphenyl derivatives Fc-C„CAR [R = C6H4AC6H5 (1), C6H4AC6H4AI (2), C6H4AC6H4ANO2 (3),
C6H3(NO2)AC6H4I (4)] and Fc-C„CAR0AC„CAR00 [R00 = Fc, R0 = C6H4AC6H4 (5), C6H3(NO2)AC6H4 (6); R00 = C6H5,
R0 = C6H4AC6H4 (7)] were synthesized from FcC„CH and biphenyl iodides by the Castro–Stephens and Sonogashira coupling reac-
tions, in which compounds 1, 2, 3, 4, 6 and 7 are new. Seven new complexes [Fc-C„CAR][Co2(CO)6] [R = C6H4AC6H5 (8),
C6H4AC6H4AI (9), C6H4AC6H4ANO2 (10), C6H3(NO2)AC6H4I (11)] and [Fc-C„CAR0AC„CAR00] [Co2(CO)6]2 [R00 = Fc,
R0 = C6H4AC6H4 (12), C6H3(NO2)AC6H4 (13); R00 = C6H5, R0 = C6H4AC6H4 (14)] were obtained by the reaction of the ligands Fc-
C„CAR and Fc-C„CAR0AC„CAR00 with Co2(CO)8, respectively. Compounds 1–7 and their complexes 8–14 have been characterized
by element analysis and spectroscopy, as well as by X-ray diffraction for 1, 4, 8, 9 and 11. The electrochemical data of compounds 1–12
have been obtained by cyclic voltammetry.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Ethynylferrocene; Coupling reaction; Biphenyl derivative; Cobalt carbonyl complex
1. Introduction
reported [14–16], but ferrocenylacetylenylbiphenyl deriva-
tives are rare [17]. Here we describe the preparation and
structural characterization of seven ferrocenylacetylenylbi-
phenyl derivatives Fc-C„CAR [R = C6H4AC6H5 (1),
C6H4AC6H4AI (2), C6H4AC6H4ANO2 (3), C6H3(NO2)A
C6H4I (4)] and Fc-C„CAR0AC„CAR00 [R00 = Fc,
R0 = C6H4AC6H4 (5), C6H3(NO2)AC6H4 (6); R00 = C6H5,
R0 = C6H4AC6H4 (7)], in which 1, 2, 3, 4, 6 and 7 are
new compounds. Compound 1 was synthesized by the Cas-
tro–Stephens coupling reaction of Fc-C„CACu and
IAC6H4AC6H5, and compounds 2–4 were obtained by
the Sonogashira coupling reaction of ethynylferrocene with
the relevant iodobiphenyl derivatives, and compounds 5–7
were prepared by a second Sonogashira coupling reaction
of ethynylferrocene with compounds 2 and 4, or ethynyl-
benzene with compound 2, respectively. Seven new cobalt
carbonyl complexes [Fc-C„CAR][Co2(CO)6] [R = C6H4
AC6H5 (8), C6H4AC6H4AI (9), C6H4AC6H4ANO2 (10),
In recent years, the design of materials for application in
molecular wires has focused on how to arrange organome-
tallic redox-active centers to enhance the capability of
transferring electrons along a conjugated molecular axis
[1–3]. The diyne Co2(CO)6 complexes are probably better
candidates and have displayed some electronic communica-
tion and interactions between redox-active centers [4–6]. A
variety of ferrocenyl p-conjugated derivatives have been
designed and synthesized by Castro–Stephens, Sonogashira
and other coupling reactions [7–13] because these com-
pounds can be used as an approach to construct linear
donor-p-conjugated spacer-accepter assemblies. p-Conju-
gated compounds with aryl groups have largely been
*
Corresponding author.
E-mail address: szj@imut.edu.cn (Q.-L. Suo).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.02.023

3154
Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
C6H3(NO2)AC6H4I (11)] and [Fc-C„CAR0AC„CAR00]-
[Co2(CO)6]2 [R00 = Fc, R0 = C6H4AC6H4 (12), C6H3(NO2)
AC6H4 (13); R00 = C6H5, R0 = C6H4AC6H4 (14)] have suc-
cessfully been synthesized by using the reactivity of the
alkyne bonds of compounds 1–7 with Co2(CO)8. The
molecular and crystal structures of compounds 1, 4 and
complexes 8, 9 and 11 have been determined by X-ray sin-
gle crystal analysis. The electrochemical properties of com-
pounds 5, 6 and 12 reveal that no significant electronic
communication between the two ferrocenyl units was
observed.
2.2. Syntheses of ferrocenylacetylenylbiphenyl derivatives
2 and 5
Ethynylferrocene (375 mg, 1.79 mmol) and 4,40- diiodo-
biphenyl (501 mg, 1.79 mmol) were stirred in diisopropyl-
amine (20 ml) with Pd(PPh3)2Cl2 (30 mg, 0.04 mmol) and
Cu(OAc)2 (4 mg, 0.02 mmol) for 20 h under reflux. The sol-
vent of the resulting orange mixture was removed in vac-
uum. The residue was dissolved in a minimal amount of
CH2Cl2. The filtrate was concentrated and subjected to
chromatographic separation on a neutral alumina column
(2 · 30 cm). Elution with hexane–dichloromethane (4:1
for 2; 2:1 for 5, v/v) afforded a yellow band 2 and an orange
band 5. Yellow crystalline 2 was obtained by re-crystalliz-
ing from hexane–dichloromethane at ꢀ20 ꢁC. Yield, 11%.
m.p. 191 ꢁC. Anal. Calc. for C24H17FeI: C, 59.05; H,
3.51. Found: C, 59.43; H, 3.54%. IR (KBr disk): m(C„C)
2. Experimental
Published procedures or extensions thereof were used to
synthesize the initial intermediates Fc-C„CH, Fc-C„CCu
[8], C6H5C6H4I, IC6H4AC6H4I, IC6H4AC6H4NO2,
IC6H3(NO2)AC6H4I [18,19]. Other chemicals were pur-
chased and used as received.
Unless stated otherwise, all reactions and manipulations
were carried out using standard Schlenk techniques under
an atmosphere of inert gases. Solvents were purified, dried
and distilled under a nitrogen atmosphere prior to use.
Reactions were monitored by TLC. Chromatographic sep-
arations and purifications were performed on 200–300
mesh silica gel or neutral alumina.
IR spectra were recorded on a Nicolet FTIR spectrom-
eter as KBr discs. Elemental analyses were carried out on
an Elementar var III-type analyzer. 1H and 13C NMR spec-
tra in CDCl3 were recorded on an Inova 500FT-MHz spec-
trometer. The mass spectra were determined using a Polaris
Q MS and a Micromass Autospec ultima- TOF instrument.
The electrochemical properties were determined with a
BAS 100A-type analyzer. Melting points were recorded
using XT-4 melting point apparatus.
1
2197 (m) cmꢀ1. H NMR (DCCl3, d): 7.16–7.79 (m, 8H,
C6H4AC6H4), 4.63 (s, 5H, C5H5), 4.95 (br s, 4H, C5H4).
13C NMR (DCCl3, d): 93.28, 123.39, 126.67, 128.76,
131.89, 137.92, 139.09, 139.96 (C6H4AC6H4), 85.47, 89.51
(C„C), 65.33, 69.05, 70.13, 71.53 (Cp). MS (EI, m/z, rela-
tive abundance): 488 (M+, 13%). Orange crystalline 5 was
obtained by re-crystallizing from THF at room tempera-
ture. Yield, 34%. m.p. 233 ꢁC (dec.). Anal. Calc. for
C36H26Fe2: C, 75.82; H, 4.60. Found: C, 75.07; H, 4.49%.
IR (KBr disk): m(C„C) 2208 (m) cmꢀ1. 1H NMR (DCCl3,
d): 7.48–7.70 (m, 8H, C6H4AC6H4), 4.42 (br s, 14H, C5H5,
C5H4), 4.70 (br s, 4H, C5H4). 13C NMR (DCCl3, d): 123.14,
126.73, 131.83, 139.51 (C6H4AC6H4), 85.59, 89.38 (C„C),
68.99, 70.10, 71.50 (Cp). MS (EI, m/z, relative abundance):
570 (M+, 9%).
2.3. Syntheses of new compounds 3, 4, 6 and 7
For the syntheses of the new compounds 3, 4, 6 and 7
see Table 1, the separation method being similar to that
of compounds 1, 2 and 5. The chemical and spectroscopic
characterization are as follows:
2.1. Synthesis of 4-ferrocenylacetylenylbiphenyl (1)
Fc-C„CCu (304 mg, 1.12 mmol) and C6H5C6H4I
(313 mg, 1.12 mmol) were dissolved in 15 ml pyridine.
The mixture solution was stirred for 8 h under reflux.
The solvent of the resulting brown mixture was removed
in vacuum. The residue was dissolved in a minimal amount
of CH2Cl2. The filtrate was concentrated and subjected to
chromatographic separation on a neutral alumina column
(2 · 30 cm). Elution with hexane–benzene (10:1, v/v) affor-
ded an orange band 1. The yellow solid 1 was obtained by
crystallizing from hexane–benzene. Yield, 46%. m.p. 149–
151 ꢁC. Anal. Calc. for C24H18Fe: C, 79.58; H, 5.01.
Found: C, 78.92; H, 4.98%. IR (KBr disk): m(C„C) 2218
Compound 3: Anal. Calc. for C24H17FeNO2: C, 70.78;
H, 4.21; N, 3.44. Found: C, 70.62; H, 4.14; N, 3.46%. IR
(KBr disk): m(C„C) 2203 (m), masNO 1507 (s), msNO 1341
2
2
(vs) cmꢀ1
.
1H NMR (DCCl3, d): 7.26–8.32 (m, 8H,
C6H4AC6H4), 4.40 (s, 5H, C5H5), 4.68 (br s, 4H, C5H4).
13C NMR (DCCl3, d): 124.18, 124.81, 127.22, 127.58,
132.05, 137.61, 146.82, 147.13 (C6H4AC6H4), 85.20, 90.62
(C„C), 65.01, 69.20, 70.17, 71.61 (Cp). MS (EI, m/z, rela-
tive abundance): 407 (M+, 100%).
Compound 4: Anal. Calc. for C24H16FeINO2: C, 54.03;
H, 3.19; N, 2.63. Found: C, 53.93; H, 3.00; N, 2.66%. IR
(KBr disk): m(C„C) 2208 (m), masNO 1527 (vs), msNO 1358
(m) cmꢀ1
.
1H NMR (DCCl3, d): 7.26–7.62 (m, 9H,
2
2
C6H4AC6H5), 4.28 (s, 5H, C5H5), 4.54 (s, 4H, C5H4). 13C
NMR (DCCl3, d): 122.88, 126.95, 127.50, 128.83, 131.78,
140.33, 140.47 (C6H4AC6H5), 85.63, 89.08 (C„C), 65.41,
68.93, 70.07, 71.47 (Cp). MS (EI, m/z, relative abundance):
362 (M+, 100%).
(s) cmꢀ1 1H NMR (DCCl3, d): 7.04–7.92 (m, 7H,
.
C6H3AC6H4), 4.33 (s, 5H, C5H5), 4.60 (br s, 4H, C5H4).
13C NMR (DCCl3, d): 94.48, 125.04, 126.71, 129.59,
131.63, 133.86, 134.70, 136.54, 137.88, 148.84
(C6H3AC6H4), 83.24, 92.54 (C„C), 63.93, 69.53, 70.25,

Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
3155
Table 1
Syntheses of new compounds 3, 4, 6 and 7
Reactantsa
Catalystb
Time (h)
Product
Yield (%)
m.p. (ꢁC)
Ethynylferrocene and 4-nitro-40-iodo-biphenyl
Ethynylferrocene and 2-nitro-4,40-diiodo-biphenyl
A
A
20
19
3
4
6
7
51
31
15
69
216–217
157–158
179–180
240 (dec.)
Ethynylbenzene and 4-iodo-40-ferrocenylethynyl-biphenyl
B
16
a
Mol ratio = 1:1 (for 3, 4, 6), 1:2 (for 7); solvent: diethylamine (for 3, 4, 6), THF/diisopropylamine (V:V = 3:1, for 7); reaction temperature: reflux (for
3, 4, 6), 60 ꢁC (for 7).
b
A: Pd(PPh3)2Cl2/CuI (1:1, 2.4 mol%), B: Pd(PPh3)2Cl2/Cu(OAc)2 (1:1, 6 mol%).
71.78 (Cp). MS (EI, m/z, relative abundance): 533 (M+,
16%).
at ꢀ20 ꢁC. Complex 8: Yield, 61%. m.p. 119–120 ꢁC. Anal.
Calc. for C30H18Co2FeO6: C, 55.59; H, 2.80. Found: C,
55.83; H, 3.19%. IR (KBr disk) m(CO) 2085 (s), 2049 (vs),
Compound 6: Anal. Calc. for C36H25Fe2NO2: C, 70.24;
H, 4.06, N, 2.28. Found: C, 69.66; H, 4.11, N, 2.39%. IR
(KBr disk): m(C„C) 2208 (m), masNO 1537 (vs), msNO 1358
1
2008 (vs) cmꢀ1. H NMR (DCCl3, d): 7.26–7.96 (m, 9H,
C6H4AC6H5), 4.21 (s, 5H, C5H5), 4.44, 4.54 (2s, 4H,
C5H4). 13C NMR (DCCl3, d): 199.45 (CO), 92.36, 126.96,
127.46, 127.57, 128.90, 137.66, 140.46, 140.85
(C6H4AC6H5), 85.26, 91.16 (C„C), 69.36, 69.66, 70.10
(Cp). MS (FAB, relative abundance): 648 (M+, 4%), 592
(M+ꢀ2CO, 41%), 564 (M+ꢀ3CO, 100%), 508 (M+ꢀ5CO,
53%), 480 (M+ꢀ6CO, 58%).
2
2
(s) cmꢀ1
.
1H NMR (DCCl3, d): 7.23–7.58 (m, 7H,
C6H3AC6H4), 4.24 (s, 14H, C5H5, C5H4), 4.50 (s, 4H,
C5H4). 13C NMR (DCCl3, d): 122.44, 123.25, 123.31,
126.81, 128.31, 128.37, 131.62, 131.86, 132.09, 139.39,
140.16 (C6H3AC6H4), 85.56, 89.25, 89.48, 92.30 (C„C),
65.19, 68.90, 69.99, 71.45 (Cp). MS (EI, m/z, relative abun-
dance): 615 (M+, 43%).
Compound 7: Anal. Calc. for C32H22Fe: C, 83.12; H,
4.76. Found: C, 83.70; H, 4.89%. IR (KBr disk): m(C„C)
2.5. Syntheses of new complexes 9, 10, 11, 12, 13 and 14
1
2203 (m) cmꢀ1. H NMR (DCCl3, d): 7.26–7.96 (m, 13H,
The syntheses of new complexes 9, 10, 11, 12, 13 and 14,
see Table 2, and the separation method is similar to that of
complex 8. The chemical and spectroscopic characteriza-
tions are as follows:
C6H4AC6H4, C6H5), 4.29 (br s, 5H, C5H5), 4.54 (br s,
4H, C5H4). 13C NMR (DCCl3, d): 124.30, 124.77, 126.69,
127.80, 131.69, 134.41, 134.60, 136.04, 149.02
(C6H4AC6H4, C6H5), 83.36, 85.26, 89.97, 92.34 (C„C),
64.95, 69.35, 70.09, 71.66 (Cp). MS (EI, m/z, relative abun-
dance): 462 (M+, 100%).
Complex 9: Anal. Calc. for C30H17Co2FeIO6: C, 46.55;
H, 2.31. Found: C, 46.52; H, 2.37%. IR (KBr disk) m(CO)
1
2080 (s), 2044 (vs), 2008 (vs) cmꢀ1. H NMR (DCCl3, d):
7.17–7.88 (m, 8H, C6H4AC6H4), 4.12 (br s, 5H, C5H5),
4.37 (br s, 4H, C5H4). 13C NMR (DCCl3, d): 199.38
(CO), 127.25, 130.24 (C6H4AC6H4), 85.20 (C„C), 69.38,
69.66, 70.12 (Cp). MS (FAB, relative abundance): 718
(M+ꢀ2CO, 9%), 690 (M+ꢀ3CO, 58%), 662 (M+ꢀ4CO,
24%), 634 (M+ꢀ5CO, 14%), 606 (M+ꢀ6CO, 18%).
2.4. Synthesis of complex
[Fc-C„CAC6H4AC6H5][Co2(CO)6] (8)
A benzene solution of equimolar amounts of com-
pounds Fc-C„CAC6H4AC6H5 (1) and Co2(CO)8 was stir-
red for 4 h at 20 ꢁC. The solvent of the resulting black
mixture was removed in vacuum. The residue was dissolved
in a minimal amount of benzene and subjected to chro-
Complex 10: Anal. Calc. for C30H17Co2FeNO8: C,
51.96; H, 2.47; N, 2.02. Found: C, 52.06; H, 2.65; N,
2.16%. IR (KBr disk) m(CO) 2077 (s), 2044 (vs), 2011
matographic separation on
(1.2 · 30 cm). Elution with hexane–benzene (10:1) afforded
black band. Crystals of the complex [Fc-
a
silica gel column
(vs) cmꢀ1 1H NMR (DCCl3, d): 7.24–8.33 (m, 8H,
.
C6H4AC6H4), 4.19 (s, 5H, C5H5), 4.44, 4.50 (d, 4H,
C5H4). 13C NMR (DCCl3, d): 199.23 (CO), 124.28,
127.58, 127.82, 130.34, 137.92, 139.98, 146.83
(C6H4AC6H4), 85.02, 90.08 (C„C), 69.50, 69.68, 70.12
a
C„CAC6H4AC6H5][Co2(CO)6] (8) were obtained by re-
crystallizing the black solid from hexane–dichloromethane
Table 2
Syntheses of new complexes 9, 10, 11, 12, 13 and 14
Reactantsa
Temperature (ꢁC)
Time (h)
Product
Yield (%)
m.p. (ꢁC)
Fc-C„CAC6H4AC6H4AI and Co2(CO)8
Fc-C„CAC6H4AC6H4ANO2 and Co2(CO)8
Fc-C„CAC6H3(NO2)AC6H4I and Co2(CO)8
Fc-C„CAC6H4AC6H4AC„C-Fc and Co2(CO)8
Fc-C„CAC6H3(NO2)AC6H4A C„C-Fc and Co2(CO)8
Fc-C„CAC6H4AC6H4AC„CAC6H5 and Co2(CO)8
a
35
50
20
60
40
40
4
9
10
11
12
13
14
65
73
90
93
74
68
150 (dec.)
131 (dec.)
121 (dec.)
110 (dec.)
134 (dec.)
168 (dec.)
0.5
0.5
1
1
1
Mol ratio = 1:1 (for 9, 10, 11), 1:2 (for 12, 13, 14); solvent: benzene.

3156
Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
(Cp). MS (FAB, relative abundance): 609 (M+ꢀ3CO,
32%), 581 (M+ꢀ4CO, 21%), 553 (M+ꢀ5CO, 6%), 525
(M+ꢀ6CO, 7%).
dance): 733 (M+ꢀ12COꢀ2Co, 7%), 615 [M+ꢀCo4(CO)12,
12%].
Complex 14: Anal. Calc. for C44H22Co4FeO12: C, 51.06;
H, 2.13. Found: C, 50.51; H, 1.97%. IR (KBr disk),
Complex 11: Anal. Calc. for C30H16Co2FeINO8: C,
43.96; H, 1.95; N, 1.71. Found: C, 43.29; H, 2.18; N,
1.67%. IR (KBr disk) m(CO) 2090 (s), 2049 (vs), 2013
m(CO): 2085 (s), 2049 (vs), 2018 (vs) cmꢀ1 1H NMR
.
(DCCl3, d): 7.21–7.96 (m, 8H, C6H4AC6H4, C6H5), 4.19,
4.21 (2s, 5H, C5H5), 4.26 (br s, 1H, C5H4), 4.44, 4.53
(2t, 3H, C5H4). 13C NMR (DCCl3, d): 199.43, 199.23
(CO), 126.82, 127.26, 127.37, 127.45, 127.95, 128.40,
128.73, 129.03, 129.27, 129.81, 130.27, 131.64, 132.21,
137.81, 138.13, 138.32, 139.82, 139.92 (C6H4AC6H4,
C6H5), 85.80, 90.06 (C„C), 69.41, 69.70, 70.01, 70.17
(Cp). MS (FAB, relative abundance): 1034 (M+, 8%),
978 (M+ꢀ2CO, 18%), 866 (M+ꢀ6CO, 37%), 810
(M+ꢀ8CO, 39%), 754 (M+ꢀ10CO, 10%), 698
(M+ꢀ12CO, 4%), 580 (M+ꢀ12COꢀ2Co, 7%), 462
(M+ꢀ12COꢀ4Co, 7%).
(vs) cmꢀ1
.
1H NMR (DCCl3, d): 7.12–8.46 (m, 7H,
C6H3AC6H4), 4.22 (br s, 5H, C5H5), 4.47 (br s, 4H,
C5H4). 13C NMR (DCCl3, d): 198.78 (CO), 92.31, 94.58,
123.79, 129.60, 132.57, 133.98, 136.62, 137.96, 140.72,
148.98 (C6H3AC6H4), 84.16, 86.52 (C„C), 69.79, 69.97,
71.67 (Cp). MS (FAB, relative abundance): 763
(M+ꢀ2CO, 16%), 735 (M+ꢀ3CO, 100%), 707 (M+ꢀ4CO,
62%), 651 (M+ꢀ6CO, 47%).
Complex 12: Anal. Calc. for C48H26Co4Fe2O12: C, 50.48;
H, 2.29%. Found: C, 50.96; H, 3.20%. IR (KBr disk), m(CO):
1
2085 (s), 2049 (vs), 2013 (vs) cmꢀ1. H NMR (DCCl3, d):
7.26–7.95 (m, 8H, C6H4AC6H4), 4.20 (br s, 14H, C5H5,
C5H4), 4.44, 4.52 (d, 4H, C5H4). 13C NMR (DCCl3, d):
199.38 (CO), 127.25, 128.75, 130.20, 138.01, 138.29,
139.40, 139.97 (C6H4AC6H4), 85.18, 90.78, 92.36,93.37
(C„C), 69.40, 69.68, 70.10 (Cp). MS (FAB, relative abun-
dance): 1059 (M+ꢀ3CO, 24%), 1031 (M+ꢀ4CO, 8%),
1003 (M+ꢀ5CO, 3%), 976 (M+ꢀ6CO, 6%).
2.6. X-ray crystallography of compounds 1, 4, 8, 9 and 11
Black crystals of compounds 1, 4, 8, 9 and 11 were
mounted on a glass fibres. All measurements were made
on Bruker SMART APEX CCD diffractometers with
˚
graphite monochromated Mo Ka (k = 0.71073 A) radia-
Complex 13: Anal. Calc. for C48H25Co4Fe2NO14: C,
48.53; H, 2.11; N, 1.18. Found: C, 48.05; H, 2.35; N,
1.23%. IR (KBr disk), m(CO): 2080 (s), 2049 (vs), 2013
tion. All data were collected at 20 ꢁC using the / and x
scan techniques. All structures were solved by direct meth-
ods and expanded using a Fourier technique [20]. An
absorption correction based on SADABS was applied [21].
All non–hydrogen atoms were refined by full matrix
least-squares on F2. Hydrogen atoms were located and
refined by a geometry method. The cell refinement, data
collection and reduction were done by Bruker SMART and
SAINT programs [22]. The solution and refinement of the
structures were performed by SHELXSL97 [23].
(vs) cmꢀ1
.
1H NMR (DCCl3, d): 7.26-8.48 (m, 7H,
C6H3AC6H4), 4.19, 4.25 (2s, 14H, C5H5, C5H4), 4.45,
4.49, 4.52 (t, 4H, C5H4). 13C NMR (DCCl3, d): 198.80,
199.29 (CO), 92.38, 92.72, 123.90, 128.34, 129.99, 132.69,
133.83, 134.73, 136.28, 139.36, 140.43, 149.18
(C6H3AC6H4), 84.23, 85.07, 86.75, 90.53 (C„C), 69.42,
69.68, 69.80, 70.01, 70.15 (Cp). MS (FAB, relative abun-
C
C
CCu
CH
C
C
C
pyridine
Fe
Fe
I
Fe
1
C R
Pd(PPh3)2Cl2
or
I-R
Fe
Cu(OAc)2
CuI
2, 3, 4
R = C6H4-C6H4-I (2), C6H4-C6H4-NO2 (3), C6H3(NO2)-C6H4I (4)
C
CH
C
C R' C C R''
Pd(PPh3)2Cl2
or
R' C C R''
I
Fe
Fe
Cu(OAc)2
CuI
5, 6, 7
R'' = Fc, R' = C6H4-C6H4 (5), C6H3(NO2)-C6H4 (6); R'' = C6H5, R' = C6H4-C6H4 (7)
Scheme 1.

Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
3157
(CO)
(CO)
3
3 Co
Co
C
C
C R
benzene
C
R
Co2(CO)8
Fe
Fe
8, 9, 10, 11
R = C6H4-C6H5 (8), C6H4-C6H4-I (9), C6H4-C6H4-NO2 (10), C6H3(NO2)-C6H4I (11)
(CO)3Co
C
Co(CO)3 (CO)3Co Co(CO)3
C
C R' C C R''
C
R'
C
C
R''
benzene
Fe
Fe
2Co2(CO)8
12, 13, 14
R'' = Fc, R' = C6H4-C6H4 (12), C6H3(NO2)-C6H4 (13); R'' = C6H5, R' = C6H4-C6H4 (14)
Scheme 2.
Table 3
Crystal data and relevant structural parameters of compounds 1, 4, 8, 9 and 11
Compounds
1
4
8
9
11
Empirical formula
Crystal system
Space group
C
24H18Fe
C24H16FeINO2
triclinic
PI
C30H18Co2FeO6
triclinic
PI
C30H17Co2FeIO6
monoclinic
P2(1)/n
10.240(4)
22.047(8)
12.559(5)
90
98.728(4)
90
2802.6(18), 4
1.835
C30H16Co2FeINO8
monoclinic
P2(1)/c
8.708(3)
23.492(9)
14.813(5)
90
98.691(6)
90
2995.4(19), 4
1.816
monoclinic
P2(1)/c
11.585(3)
7.3723(19)
20.928(6)
90.00
101.345(5)
90.00
1752.5(8), 4
1.373
˚
a (A)
9.198(4)
11.899(5)
18.935(8)
83.676(6)
89.663(6)
82.237(7)
2040.8(14), 4
1.735
9.963(7)
15.111(11)
19.554(14)
71.002(11)
87.090(12)
79.626(13)
2738(3), 4
1.572
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
Volume, Z
Dcalc (g/cm3)
l (mmꢀ1
F(000)
)
0.862
752
2.272
1048
1.762
1304
2.825
1512
2.654
1600
h Range (ꢁ)
1.79–25.01
7020
3088
3.127–25.24
8555
7052
1.10–25.01
11600
9507
1.85–26.01
12767
5523
1.64–25.01
12454
5259
Reflections collected
Independent reflections
Completeness to h (%)
Maximum and minimum
transmission
99.7
98.2
98.5
99.9
99.7
0.9342 and 0.8465
0.8047 and 0.6593
0.8719 and 0.7780
0.8056 and 0.6020
0.7772 and 0.5567
Data/restraints/parameters
Goodness-of-fit
3088/0/226
0.955
7052/0/523
0.933
9507/0/703
0.842
5523/0/361
0.930
5259/0/388
1.033
Final R indices [I > 2r(I)]
R1, 0.1081; wR2,
0.1047
R1, 0.0446; wR2,
0.1059
R1, 0.0551; wR2,
0.1138
R1, 0.0304; wR2,
0.0665
R1, 0.0688; wR2,
0.1493
R-indices (all data)
R1, 0.2561; wR2,
0.1333
R1, 0.0656; wR2,
0.1132
R1, 0.1207; wR2,
0.1422
R1, 0.0444, wR2,
0.0708
R1, 0.1046, wR2,
0.1666
Largest difference in peak and hole 0.331 and ꢀ0.313
0.627 and ꢀ1.015
0.713 and ꢀ0.384
0.642 and ꢀ0.562
1.599 and ꢀ0.958
ꢀ3
˚
(e A
)
3. Results and discussion
3.1. Syntheses and characterizations of the
ferrocenylacetylenylbiphenyl derivatives and their complexes
The coupling reactions carried out in this work are sum-
marized in Scheme 1. The addition reactions of the ligands
Fc-C„CAR and Fc-C„CAR0AC„CAR00 with Co2(CO)8
are summarized in Scheme 2. The complexes 8, 9, 10, 11, 12,
13 and 14 were prepared by the addition reaction between
the CoACo bond of Co2(CO)8 and the C„C triple bond
of the ligands Fc-C„CAR and Fc-C„CAR0AC„CAR00
Fig. 1. Molecular structure of compound 1.

3158
Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
Fig. 2. Molecular structure of compound 4.
with the mole ratios of Co2(CO)8 to ligand fixed at 1:1 and
1:2, respectively. The compounds are yellow for 1 and 2 and
orange for 3, 4, 5, 6 and 7, and they are air-stable crystalline
compounds which are slightly soluble in non-polar solvents
such as hexane, and easily soluble in benzene and polar sol-
vents such as dichloromethane. The complexes 8–14 are
black crystals and their solubilities are similar to the corre-
sponding ligands. The IR spectra (2077–2018 cmꢀ1) con-
firm that there are coordinated Co2(CO)6 species with
C„C triple bonds in complexes 8–14. The composi-
tions and structures of compounds 1–14 are further proved
The molecules of compounds 1, 4, 8, 9 and 11 are con-
stituted of a p-conjugated alkynyl system with terminal
ferrocenyl and biphenyl or substituted biphenyl units,
respectively. In
(1.183 A) shows there is a carbon–carbon triple bond.
1 the bond distance C(11)–C(12)
˚
˚
The bond distances C(10)–C(11) (1.45 A) and C(12)–
˚
C(13) (1.44 A) are shorter than that of C(16)–C(19)
˚
(1.51 A) as a result of stronger electron delocalization
1
by the data of their element analyses, H, 13C NMR and
MS.
3.2. Molecular structures of compounds 1, 4, 8, 9 and 11
The molecular structures of compounds 1, 4, 8, 9, 11
were determined by X-ray single crystal analysis. Crystal
data and relevant structural parameters are enumerated
in Table 3. The structures of compounds 1, 4, 8, 9 and
11, with the atom numbering scheme, are shown in Figs.
1–5, respectively, and selected bond lengths and angles
are listed in Table 4.
Fig. 4. Molecular structure of compound 9.
Fig. 3. Molecular structure of compound 8.
Fig. 5. Molecular structure of compound 11.

Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
3159
between the C„C bond (sp-C) and biphenyl (sp2-C) or
the C„C bond (sp-C) and ferrocenyl group (sp2-C) than
that between two phenyl groups (two sp2-C). The bond
angle data in Table 2 demonstrate that the linear structure
of compound 1 is altered to a non-linear structure in 8,
while the alkyne bond of 1 is coordinated to a Co2(CO)6
unit. The molecular structures of compounds 4 and 11
are similar to the structures of compounds 1 and 8, respec-
tively (see Figs. 2, 5 and 1, 3). The coordinated Co2(CO)6
units with the C„C bond in complexes 8, 9 and 11 are all
approximately tetrahedral l-alkyne dicobalt moieties. The
alkyne bond adopts a typical l2–g2 coordination fashion
with the alkyne bond lying essentially perpendicular to the
CoACo bond in the C2Co2 unit. The average CoACo
ring. The data of the dihedral angles (1.97ꢁ for 1, 0.88ꢁ
for 4, 4.01ꢁ for 8, 5.58ꢁ for 9 and 2.97ꢁ for 11) between
the two Cp planes in compounds 1, 4, 8, 9 and 11 reveal
that the two Cp planes are nearly parallel in 4, but are
slightly deviated from parallel in 1, 8, 9 and 11.
3.3. Electrochemical properties of compounds 1–12
The electrochemical properties of compounds 1–12 have
been studied by cyclic voltammetry at 298 K in a standard
three-electrode system with n-NBu4ClO4(TBAP) in CH2Cl2
solution as the supporting electrolyte. The results are given
in Table 5.
For compounds 1–7 and complexes 8, 10 and 12 the
usual electrochemically quasi-reversible ferrocene (0/1+)
peak couples and a one-electron redox process were
observed (see Table 1), but for complexes 9 and 11 an irre-
versible redox process was observed. Only a pair of redox
peaks appears, which reveals that there are no Fe–Fe inter-
actions in the di-ferrocenyl compounds 5, 6 and 12 through
the conjugated biphenyl ethynyl bridges [17]. However, a
redox behavior study of ethynyl-bridged ferrocenes, such
as the Fc-(C„C)2-Fc ligand and its clusters, demonstrates
two one-electron redox processes, which show there are
Fe–Fe interactions [24]. The irreversible reduction peaks
within range Epc = ꢀ 0.55 to ꢀ0.88 V in complexes 8–12
were regarded as the result of a reducing process on the
Co2(CO)6 moieties. Although there are substituted elec-
tron-withdrawing groups on the biphenyl rings in com-
pounds 2, 3, 4, 6, 9, 10 and 11, and the coordinated
Co2(CO)6 units for complexes 8–12, no significant varia-
tion of E0 was observed.
˚
bond distance (2.46 A) is typical of classical alkyne dico-
˚
balt complexes. The average CAC bond length (1.34 A)
of the C2Co2 fragments shows a bond distance of the
coordinated C„C bond located in the scope of a CAC
double bond. In complexes 8, 9 and 11 the Co2(CO)6 units
coordinated to the alkyne bond are in a trans configura-
tion with the biphenyl and ferrocenyl groups, and the
two terminal groups (biphenyl or substituted biphenyl
and ferrocenyl groups) are orientated cis to each other
(see Fig. 3–5).
In compounds 1, 4, 8, 9 and 11, the data of the dihedral
angles (40.12ꢁ for 1, 52.52ꢁ for 4, 26.30ꢁ for 8, 35.41ꢁ for 9
and 57.51ꢁ for 11) between the two phenyl rings are differ-
ent from each other, and have been affected by the substi-
tuted group on the biphenyl ring and the coordinated
Co2(CO)6 unit with the alkyne. The dihedral angle between
the two phenyl rings in 1 is smaller than that in 4 because of
the effect of the substituted group (NO2) on the phenyl
Table 4
˚
Selected bond lengths (A) and angles (ꢁ) for 1, 4, 8, 9 and 11
Bond lengths
Bond angles
1
C(10)–C(11)
C(11)–C(12)
1.45(1)
1.18(1)
C(12)–C(13)
C(16)–C(19)
1.44(1)
1.51(1)
C(10)–C(11)–C(12)
C(11)–C(12)–C(13)
179.2(1)
177.6(1)
C(15)–C(16)–C(19)
C(16)–C(19)–C(20)
120.3(8)
120.8(1)
4
C(10)–C(11)
C(11)–C(12)
1.44(6)
1.18(6)
C(12)–C(13)
C(16)–C(19)
1.44(6)
1.48(6)
C(10)–C(11)–C(12)
C(11)–C(12)–C(13)
178.3(5)
176.5(5)
C(17)–C(16)–C(19)
C(16)–C(19)–C(24)
123.3(4)
121.6(4)
8
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
Co(1)–Co(2)
1.44(9)
1.33(8)
1.46(8)
2.46(2)
Co(1)–C(12)
Co(1)–C(13)
Co(2)–C(12)
Co(2)–C(13)
1.99(7)
1.95(7)
1.96(6)
1.97(6)
C(11)–C(12)–C(13)
C(12)–C(13)–C(14)
C(13)–C(14)–C(15)
C(18)–C(17)–C(20)
145.9(6)
144.5(7)
122.0(6)
121.6(6)
Co(1)–C(12)–C(13)
Co(1)–C(13)–C(12)
Co(2)–C(12)–C(13)
Co(2)–C(13)–C(12)
68.6(4)
71.9(4)
70.5(4)
69.7(4)
9
C(16)–C(17)
C(17)–C(18)
C(18)–C(19)
Co(1)–Co(2)
1.45(4)
1.33(4)
1.46(4)
2.46(8)
Co(1)–C(17)
Co(1)–C(18)
Co(2)–C(17)
Co(2)–C(18)
2.00(3)
1.94(3)
1.95(3)
1.99(3)
C(16)–C(17)–C(18)
C(17)–C(18)–C(19)
C(18)–C(19)–C(20)
C(21)–C(22)–C(25)
144.2(3)
141.9(3)
122.2(3)
120.9(3)
Co(1)–C(17)–C(18)
Co(1)–C(18)–C(17)
Co(2)–C(17)–C(18)
Co(2)–C(18)–C(17)
68.2(2)
72.4(2)
71.8(2)
68.7(2)
11
C(10)–C(11)
C(11)–C(12)
C(12)–C(19)
Co(1)–Co(2)
1.44(1)
1.34(1)
1.45(9)
2.46(2)
Co(1)–C(11)
Co(1)–C(12)
Co(2)–C(11)
Co(2)–C(12)
2.01(7)
1.97(7)
1.96(7)
1.97(7)
C(10)–C(11)–C(12)
C(11)–C(12)–C(19)
C(12)–C(19)–C(20)
C(22)–C(25)–C(26)
144.8(7)
141.5(7)
120.5(7)
121.8(7)
Co(1)–C(11)–C(12)
Co(1)–C(12)–C(11)
Co(2)–C(11)–C(12)
Co(2)–C(12)–C(11)
68.6(4)
72.1(4).
70.6(4)
69.5(4)

3160
Q.-L. Suo et al. / Polyhedron 26 (2007) 3153–3160
Table 5
and for 9. These data can be obtained free of charge via
Voltammetric dataa
http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from
the Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-
033; or e-mail: deposit@ccdc.cam.ac.uk. Supplementary
data associated with this article can be found, in the online
version, at doi:10.1016/j.poly.2007.02.023.
Compound
Epc
Epa
ipc/ipa
E0 (0/1+)
Reduction
of Co, Epc
1
2
0.33
0.36
0.44
0.42
0.34
0.35
0.36
0.34
0.37
0.37
0.48
0.26
1.28
1.19
1.21
1.19
1.50
1.40
1.24
1.40
1.09
1.21
1.10
1.37
0.96
1.01
0.82
0.93
1.00
1.00
1.04
0.99
0.19
0.92
0.21
0.89
0.81
0.78
0.83
0.81
0.92
0.88
0.80
0.87
0.73
0.79
0.79
0.82
3
4
5
6
References
7
8
ꢀ0.72
ꢀ0.58
ꢀ0.88
ꢀ0.55
ꢀ0.77
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10
11
12
Epc = cathodic peak potential (V); Epa = anodic peak potential (V);
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a
Platinum electrode (Ag/Ag+ standard) in
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Ferrocenylacetylenylbiphenyl and bisferrocenylacetyle-
nyl-biphenyl derivatives could be synthesized by Sonogash-
ira coupling and a second Sonogashira coupling reaction,
respectively, and their cobalt coordinated complexes could
be obtained by the addition reaction of Co2(CO)6 units to
the alkyne bond. The molecular structures of complexes 8,
9 and 11 show the Co2(CO)6 units coordinated to the
alkyne bond are in a trans configuration with the terminal
biphenyl derivatives and ferrocenyl groups. The data of
dihedral angles reveal two phenyl rings of biphenyl deriva-
tives in compounds 1, 4, 8, 9 and 11 are deviated from
parallel.
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We are grateful to the Specialized Research Fund for the
Doctoral Program of Higher Education of China
(20060128001) and the Natural Science Foundation of
Inner Mongolia for financial support of this work.
Appendix A. Supplementary material
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CCDC 625423, 625424, 625425, 625426 and 625427 con-
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